GitLab provides liveness and readiness probes to indicate service health and
reachability to required services. These probes report on the status of the
database connection, Redis connection, and access to the filesystem. These
endpoints can be provided to schedulers like Kubernetes to hold
traffic until the system is ready or restart the container as needed.

IP whitelist

To access monitoring resources, the client IP needs to be included in a whitelist.

Status

On failure, the endpoint will return a 500 HTTP status code. On success, the endpoint
will return a valid successful HTTP status code, and a success message.

Access token (Deprecated)

Note:
Access token has been deprecated in GitLab 9.4
in favor of IP whitelist

An access token needs to be provided while accessing the probe endpoints. The current
accepted token can be found under the Admin area ➔ Monitoring ➔ Health check
(admin/health_check) page of your GitLab instance.